First Results Of A Fresnel-Zone Based Posterior Chamber Phakic Iol With A Central Port To Correct Myopia And Myopic Astigmatism

To demonstrate the clinical outcome, safety, predictability and efficacy with a novel phakic intraocular lens based on Fresnel-zone technology to correct myopia and myopic astigmatism without the requirement of an iridotomy or iridectomy due to a central port.

Medipolis Eye Center, Antwerpen, Belgium

This interventional study was conducted within the obligatory Post Market Clinical Follow-Up. Twenty-three eyes of 12 patients with a median age 36.5 ± 7.7 years were included (7 females/5 males). Patients were followed over 3 months. Refraction, visual acuity, intraocular pressure (IOP), difference in endothelial cell count, and lens vault were recorded. Lens calculation was performed with matrix based vergence tracing. Sizing was performed with direct sulcus measurement using an anterior segment optical coherence tomographer.

The pre-OP spherical equivalent refraction was -8.4 D ± 4.1 D [-17.5 to -3.75] and cylinder was 1.6 D ± 1.0 D [-3.5 to 0.0]. Pre-OP UDVA and CDVA [logMAR] was 1.39 ± 0.87 and 0.05 ± 0.08.

Postoperative spherical equivalent refraction at 3 months was 0.01 D ± 0.41 D [-0.5 to +1.25], cylinder was -0.48 D ± 0.78 D [-3.5 to 0.0]. Two eyes ended up with hyperopic refraction, one with initial high myopia of -16 D and one with crosslinked keratoconus. UDVA was logMAR 0.06 ± 0.18 [range 0.6 to -0.1] and CDVA logMAR 0.00 ± 0.10 [range 0.2 to -0.1]. Average gain in UDVA was 1.33 logMAR and for CDVA 0.04 logMAR. One eye lost one line, 11 eyes retained the CDVA and 11 eyes gained 1 line. There was no reduction in endothelial cell count and the vault was 781 ± 275 µm [range 216 to 1210]  and IOP was 14.4 ± 3.5 mmHg [range 9 to 23].

This first in human Fresnel-zone–based posterior chamber phakic IOL demonstrated favorable short-term safety and refractive performance in this initial clinical series and does not require vault prediction for size estimation and remaining stable during the first 3 months. The thin cross section of the IOL provides more space in the anterior chamber in comparison with conventional optical designs. Refractive outcomes were predictable, with good visual acuity results and no significant endothelial cell loss. The thin optic profile may contribute to improved anterior chamber dynamics, even in highly myopic eyes. Longer follow-up and larger cohorts are required to confirm long-term stability, endothelial safety, and optical quality.